Case Study

A 22-year-old gravida 2, para 1 woman at 28 weeks’ gestation presented to the triage area for evaluation with a 24-hour history of worsening abdominal pain, nausea, anorexia, and fever. Her medical history was unremarkable. She previously had a vaginal delivery of a healthy baby at term. On admission, her vital signs were stable. The Emergency Department team immediately contacted the surgical team to investigate a potential surgical diagnosis, such as acute appendicitis. The junior surgeon performing the initial assessment was hesitant to recommend any form of imaging because of the pregnancy. The patient subsequently spent several hours in the Emergency Department without any investigations or interventions. Her condition worsened over the next few hours. Finally, the obstetric team was consulted, and a presumptive diagnosis of appendicitis was made. The fetal condition was evaluated by the obstetric team at the same time and found to be stable. The patient was then prepared for open surgery, with the attending surgeon adamant that laparoscopy was contraindicated in pregnancy. Unfortunately, during this period, the patient became severely septic, with fetal compromise. This resulted in a joint obstetric/surgical procedure that included an urgent cesarean delivery together with an open appendectomy. Following a protracted period in the high-dependency unit, the patient made a full recovery and was discharged 10 days later with her healthy baby.

Key Points

• 
  

  Essential to an understanding of the risks of nonobstetric surgery during pregnancy is an awareness of the physiologic changes during pregnancy.

  
  
• 
  

  The available evidence-based literature suggests that surgery during pregnancy is much safer than previously thought.

  
  
• 
  

  There is no strong evidence as to the preferred way to perform an appendectomy (open or laparoscopic) during pregnancy from a fetal or maternal safety viewpoint.

  
  
• 
  

  Delay in the diagnosis and treatment of conditions such as acute appendicitis dramatically increases maternal and fetal morbidity and mortality.

  
  
• 
  

  The perioperative team should aim to minimize the operative time and use the most appropriate anesthesia technique with the safest anesthetic drugs.

  
  
• 
  

  Preterm delivery and fetal loss remain the most prevalent concerns for nonobstetric surgery during pregnancy. Some surgeons are hesitant to perform laparoscopic surgery during the third trimester due to the risk of greater fetal loss and potentially increased surgical complication rates.

  
  
• 
  

  In cases of appendectomy in pregnancy, the most experienced surgical team should be used to minimize complications, and the decision to perform a laparoscopy versus open procedure should depend on the expertise of the surgical team.

Discussion

It is generally estimated that up to 2 percent of parturients undergo nonobstetric surgery during pregnancy. The most common nonobstetrical surgical emergencies complicating pregnancy are acute appendicitis, cholecystitis, and intestinal obstruction.¹ Nonobstetric surgery during pregnancy must initiate a discussion about how the physiologic changes of pregnancy affect the mother while also being highly sensitive to the effects of surgery and anesthesia on the unborn fetus. Ideally, elective surgery should be postponed until the postpartum period, and if possible, it also should be avoided during the organogenesis phase of the first trimester.

The multidisciplinary team must be cognizant of the physiologic changes of pregnancy, especially those involving the cardiovascular, respiratory, and gastrointestinal systems. Major cardiovascular changes include an increase in cardiac output by 30–40 percent during the first trimester and up to 50 percent at term.² Blood pressure decreases secondary to reduced systemic vascular resistance and can result in the supine hypotensive syndrome. In cases of trauma or infection, this syndrome can alter uteroplacental perfusion significantly, as well as maternal hemodynamic stability. Changes in cardiac output can speed up the rate of intravenous (IV) drug induction and alter rates of uptake and removal of drugs from the maternal circulation, altering the depth of anesthesia. Significant respiratory changes secondary to increased progesterone levels lead to increases in minute ventilation. The growing fetus causes anatomic changes in the location of the diaphragm, resulting in a significant 20 percent reduction in functional residual capacity (FRC). These changes, together with increases in alveolar ventilation, result in an increased risk of hypoxemia during periods of apnea as well as rapid uptake and distribution of inhaled anesthetics. In addition, airway changes include laryngeal and pharyngeal edema as well as capillary engorgement of the mucosal lining of the airway. These changes may make securing the airway a potential challenge.³

While almost every system in the parturient undergoes some alteration, the gastrointestinal system is also very relevant. Recently, Wong et al.⁴ found no change in gastric emptying in obese and nonobese pregnant women compared with nonpregnant patients. While gastric emptying may not be delayed, there certainly are changes such as a reduction in lower esophageal sphincter tone and increases in intragastric pressure due to the gravid uterus. An increase in gastric acid secretion has been seen in parturients as well, although the finding is not consistent. It is not clear whether these gastrointestinal changes increase the risk of parturients developing acute appendicitis and other abdominal pathology. Of course, in acute abdominal pathology, as seen in the Case Study, “full stomach” considerations are valid irrespective of the patient’s pregnancy.

During pregnancy, the well-being of the fetus is paramount. Teratogens are drug and environmental agents that increase the incidence of non-chance-related defects. Fetal organs develop throughout gestation, but days 15–60 are essential for organogenesis in humans. For the fetus, the greatest risk involves spontaneous abortion, premature labor, and preterm delivery, which can result in significant morbidity and mortality to the newborn. And while no anesthetic agent or technique is superior, each agent and technique carries risks that must be evaluated. Finally, it is not certain whether the underlying medical condition requiring surgery, surgery itself, or the anesthetic agents used poses the greatest risk to the fetus, but all should be minimized during pregnancy. The most current evidence suggests that no anesthetic agents, including the previously suspect nitrous oxide and benzodiazepines, are teratogenic in humans.

The Case Study illustrates the difficulty that imaging and diagnosis pose for both maternal and fetal outcome. In the case of acute appendicitis, a 24-hour delay of surgery after presentation can lead to a 66 percent increase in the perforation rate as well as a 20 percent rate of fetal loss compared with a 5 percent rate of fetal loss with uncomplicated acute appendicitis.⁵ Radiation to the fetus from x-rays and CT scans has been a major factor in delays in diagnosis. Most physicians are concerned about the potential negative effects on the developing fetus. Radiation comes in two types: ionizing and nonionizing. Examples of nonionizing radiation include ultrasound and MRI. Examples of ionizing radiation include x-rays and gamma rays. Ionizing radiation originates from space and natural resources and exists everywhere, including soil, water, and air. On average, a person is exposed to some discreet level of background radiation every year.⁶ The precise amount of background radiation exposure varies in different parts of the world depending on the altitude and the quality of the atmosphere. When looking specifically at the effects of radiation on a fetus, it is important to first note that the radiation dose that a pregnant woman is exposed to or absorbs may not directly transfer to the fetus. A fetus is partly protected from radiation injury by a pregnant woman’s surrounding soft tissues and uterus, both of which generally stop alpha and beta particles from penetration if they are not ingested, injected, or inhaled.⁷ However, gamma and x-rays directed toward the abdomen of a pregnant woman who is not appropriately shielded can reach and harm a fetus. The effects of ionizing radiation on an embryo and fetus can include pregnancy loss, malformations, neurobehavioral abnormalities, fetal growth restriction, and cancer.⁸ The American College of Obstetricians and Gynecologists (ACOG) has indicated that the threshold for medical concern, particularly regarding congenital malformations, should be lowered to 50 mGy (5 rad).⁹ It is important to remember that there is a less than 0.001 rad exposure per chest x-ray. According to these statistics, it would take thousands of x-rays to cause significant risk. However abdominal shields should be placed when possible, and time to exposure should be minimized.

Now, with the presence of ultrasonography and MRI scanning that provide minimal radiation exposure to the unborn fetus and a knowledgeable multidisciplinary team with an obstetric anesthesiologist to facilitate imaging and surgery, delays should not occur.

The long term effects of surgery and anesthesia on the fetus are highly controversial. Animal models have shown that exposure to anesthetic agents during a period of synaptogenesis in rats results in neuronal apoptosis and can infer later-in-life learning defects. These data are difficult to extrapolate to human models. Several provocative studies have recently shown an association of surgery and anesthesia with both learning disabilities and deviant behavior.¹⁰ In addition, in 2017 the U.S. Food and Drug Administration (FDA) issued a warning that repeated or lengthy use of general anesthesia and sedation during surgery or procedures in children younger than 3 years old or pregnant women during the 3rd trimester or lasting greater than 3 hours may affect fetal brain development and cognitive behavior.¹¹

Once a decision is made to proceed with surgery, an anesthetic technique is selected. If at all possible, regional and neuraxial techniques should be used because they confer minimal transfer of drugs and agents to the fetus. If general anesthesia is used, animal models suggest that fetal skeletal abnormalities or death may followed repeated or prolonged exposure of mice to anesthetic concentrations of volatile agents, but no evidence has suggested reproductive toxicity with either sevoflurane or desflurane in clinical concentrations.¹² Nitrous oxide use has been studied extensively in rat models, and the literature suggests that the teratogenicity is complex and involves the inhibition of methionine synthase. Teratogenesis has been associated with the use of any of the commonly employed induction agents, including the barbiturates, ketamine, and the benzodiazepines, as well as opioids, when given in clinical doses.¹³ It is common to see fetal heart rate variability with opioids and induction agents, but these changes may indicate an anesthetized fetus and are not of concern in the presence of maternal stability. Toxicity is not associated with small doses of muscle relaxants, and no evidence supports teratogenicity associated with any local anesthetic used clinically in humans.¹⁴

Continuous fetal heart rate monitoring during surgery certainly can be performed if the surgical site allows, and someone who can interpret the cardiotocography (CTG) monitor should be present. A plan also must be in place when faced with persistent nonreassuring or pathologic CTG tracings. The ACOG has stated that “the decision to use fetal monitoring should be individualized and, if used, should be based on gestational age, type of surgery, and facilities available.”¹⁵

The decision to perform open versus laparoscopic surgery is a controversial one and should be based on the skill level of the surgical team for optimal safety of the mother and fetus. When laparoscopic surgery was in its infancy, some argued that laparoscopy was contraindicated during pregnancy owing to concerns for uterine injury and fetal perfusion. As surgeons have gained more experience with laparoscopy, it has become the preferred treatment for many surgical diseases in pregnant patients. Concerns for the fetus during laparoscopy include fetal trauma, fetal acidosis from absorbed carbon dioxide, and decreased maternal cardiac output and resulting decrease in uteroplacental perfusion from iatrogenic increases in intraabdominal pressure.

Benefits of laparoscopy during pregnancy appear similar to those in nonpregnant patients, including less postoperative pain, less postoperative ileus, decreased length of hospital stay and faster return to work. There are many advantages of laparoscopy in pregnant patients as well, including decreased fetal respiratory depression due to diminished postoperative narcotic requirements, lower risk of wound complications, diminished postoperative maternal hypoventilation, and decreased risk of thromboembolic events.¹⁶ Laparoscopic treatment of acute abdominal disease has the same indications in pregnant and nonpregnant patients and may even confer some benefit. The improved visualization in laparoscopy may reduce the risk of uterine irritability by decreasing the need for uterine manipulation. Decreased uterine irritability results in lower rates of spontaneous abortion and preterm delivery.¹⁷ Laparoscopic appendectomy may be performed safely in pregnant patients with appendicitis, and laparoscopic cholecystectomy is the treatment of choice in the pregnant patient with gallbladder disease regardless of trimester.¹⁸